It is well known in the art that connecting a ring to a load member can be utilized to lift and manipulate the load member such as die sets or molds. Further, it is well known that a ring attached to a load member can be used to secure the load member such as for transportation of the load member. Fuller U.S. Pat. No. 6,068,310, for example, discloses a side-pull style hoist ring which pivotally secures a load bearing ring to a load member and is incorporated by reference herein as background information for side-pull hoist rings.
Another style of hoist rings which is utilized to lift or secure a load member is disclosed in Schron, Jr. U.S. Pat. No. 5,634,734 and U.S. Pat. No. 5,743,576. The patents to Schron Jr. disclose a center-pull style hoist ring which also fastens a load bearing ring to a load member. As with the side-pull hoist ring, as is disclosed in Fuller, the center-pull hoist ring disclosed in Schron Jr. provides rotation about a first and a second axis which are perpendicular to one another. This allows the load bearing ring to automatically pivotally extend towards the direction of the applied force. However, with center-pull style hoist rings, the first and second axes intersect one another, which is not the case with side-pull a hoist rings as is disclosed in Fuller. Schron Jr. is also incorporated by reference as background information.
It is well known in the art that by securing a load ring to an object, the load ring can be utilized to lift the object or to secure the object. In this respect, a hook attached to a hoisting device may be utilized to lift heavy objects such as molds and die sets by interengaging with the hoist ring. In addition, straps or tie downs can be attached to the ring to secure an object during shipment. Earlier load bearing rings utilized rigid ring mechanisms fixedly attached to the load member. The common attaching method is by directly threading the load ring into a threaded bore on the surface of the load member. This design is simple but has many problems in that by directly threading the rigid load ring to the surface of the object, the load ring may loosen, which would require subsequent tightening thereof. In addition, since the load ring is fixedly engaged to the load member, it is not capable of automatically pivotally extending toward the direction of the applied force. Therefore, a bending moment is produced in the direction of the applied force when the lifting device applies the force to the load member. The bending moment requires stronger materials to be utilized or additional reinforcement of the load ring. In addition, large loads can damage the threads of the threaded bore. In order to overcome the shortcomings of the rigid ring, hoist rings which allow the load bearing ring to pivot toward the direction of the applied force were developed. However, providing a structure that allows pivotal movement of the load ring disadvantageously increases the cost of the hoist ring device. In this respect, allowing pivotal movement of the load ring about one or two axes increases the number of components in the hoist ring and further increases the complexity of the manufacturing process.
Another disadvantage found in the prior art is that in order to allow the load bearing ring to pivot to the direction of the applied force, intricate components are required, which further add to the expense of the manufacturing process. Further, in order to produce a pivotable hoist ring that acts as a single component in both the mounted and unmounted condition, complicated support members are required to handle the applied force and to prevent inadvertent disassembly when the device is removed from the load member while still allowing for pivotal movement about two axes. In addition, due to the substantial forces created by the applied force, high strength materials are utilized for the support member which typically do not possess properties favorable for machining. This further adds to the cost of the hoist ring device.
In accordance with the present invention, an improved hoist ring is provided which requires fewer components and fewer machining steps while still providing a rigid hoist ring with a load bearing ring capable of pivoting automatically in the direction of the applied force during the lifting or securing procedure. More particularly, a hoist ring in accordance with the present invention includes a support member which allows a post, which fixedly engages the threaded bore of a load member, to also partially interengage with a load bearing ring to retain the load bearing ring in the support member, while still allowing pivotal movement of the load bearing ring about two axes. In providing a support member in accordance with the present invention, the number of components and the number of machining steps are advantageously reduced even though the strength of the hoist ring is maintained and the components of the hoist ring are retained by the support member even when the hoist ring is removed from the load member. In addition, by providing a support member which is a unified component, strength is increased while the number of component parts is reduced.
The foregoing advantages are achieved in accordance with the present invention by utilizing a support member having a passage for receiving the post which partially intersects with a ring slot that is generally perpendicular to the passage such that a portion of the post, when it is received in the passage, interengages with the load ring in the ring slot to retain the load ring in the ring slot. Further, the interengagement between the portion of the post and the load ring does not reduce the ability of the load ring to freely pivot within the slot or the support member to freely pivot about the post.
It is accordingly an outstanding object of the present invention to provide a hoist ring which pivotally interengages with a load member to allow the load bearing ring to automatically adjust to the direction of the applied force during the lifting or securing procedure.
Another object is the provision of a hoist ring of the foregoing character which requires fewer components and fewer manufacturing steps than hoist rings heretofore available.
A further object is the provision of a hoist ring of the foregoing character which is less expensive to produce while maintaining its structural integrity.
Still another object of the present invention is the provision of a hoist ring of the foregoing character which is joined together in such a way that the components thereof are retained therein even when the hoist ring is removed from the load member.
Yet another object of the present invention is the provision of a hoist ring of the foregoing character which utilizes a unified central support member which provides rotation of the load ring about two axes.
A further object of the present invention is the provision of a hoist ring of the foregoing character which is easy to use.